1. Field of the Invention
The present invention relates to a film deposition method and a film deposition apparatus that deposit a reaction product of at least two kinds of reaction gases that react with each other by alternately supplying the gases to the substrate, and more specifically to a film deposition method and a film deposition apparatus appropriate for filling a concave portion formed in a surface of the substrate with the reaction product.
2. Description of the Related Art
A process of fabricating a semiconductor integrated circuit (i.e., IC) includes a process of filling a concave portion formed in a surface of a substrate, such as a trench, a via hole, or a space in a line-space pattern, with silicon oxide. For example, as disclosed in Japanese Patent No. 4661990, in filling the concave portion with the silicon oxide, in order to prevent a void from being caused in the silicon oxide film filled in the concave portion, a film deposition method that can deposit the silicon oxide film along the concave portion (in a conformal manner) is preferably adopted.
In filling the concave portion with the silicon oxide by the film deposition method that can deposit a film in a conformal manner, as the silicon oxide film deposited on both side walls of the concave portion becomes thick, surfaces of the oxide film on the side walls become closer to each other, and eventually contact near the center of the concave portion, by which the concave portion is filled with the silicon oxide film. However, a contact surface (i.e., a seam) where the silicon oxide film on both side walls contacts with each other may separate from each other if the silicon oxide film on the side walls in the concave portion contracts in a heating process performed after the concave portion filling process, and may cause a void within the silicon oxide film. Moreover, in an etching process performed after the concave portion filling process, the etching may be accelerated along the seam, which may cause the void.